[libcamera-devel] [PATCH v12 1/3] libcamera: controls: Add frame duration control

[Naushir Patuck]

Hi Laurent,


On Wed, 20 Jan 2021 at 11:50, Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> Hi Naush,
>
> Thank you for the patch.
>
> On Tue, Jan 19, 2021 at 03:30:45PM +0000, Naushir Patuck wrote:
> > Add an int64_t array control (controls::FrameDurations) to specify the
> > minimum and maximum (in that order) frame duration to be used by the
> > camera sensor.
> >
> > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
> > Tested-by: David Plowman <david.plowman at raspberrypi.com>
> > Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >  src/libcamera/control_ids.yaml | 36 ++++++++++++++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >
> > diff --git a/src/libcamera/control_ids.yaml
> b/src/libcamera/control_ids.yaml
> > index 6d6f0fee508b..36c37161a3d5 100644
> > --- a/src/libcamera/control_ids.yaml
> > +++ b/src/libcamera/control_ids.yaml
> > @@ -306,6 +306,42 @@ controls:
> >          maximum valid value is given by the
> properties::ScalerCropMaximum
> >          property, and the two can be used to implement digital zoom.
> >
> > +  - FrameDurations:
> > +      type: int64_t
> > +      description: |
> > +          The minimum and maximum (in that order) frame duration,
> > +          expressed in micro-seconds.
>
> s/micro-seconds/microseconds/
>
> (The indentation should be 2 spaces btw)
>
> I'll handle this when applying.
>

Thank you!  Apologies that I missed fixing those typos you pointed out
earlier.

Regards,
Naush


>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>

> > +
> > +          When provided by applications, the control specifies the
> sensor frame
> > +          duration interval the pipeline has to use. This limits the
> largest
> > +          exposure time the sensor can use. For example, if a maximum
> frame
> > +          duration of 33ms is requested (corresponding to 30 frames per
> second),
> > +          the sensor will not be able to raise the exposure time above
> 33ms.
> > +          A fixed frame duration is achieved by setting the minimum and
> maximum
> > +          values to be the same. Setting both values to 0 reverts to
> using the
> > +          IPA provided defaults.
> > +
> > +          The maximum frame duration provides the absolute limit to the
> shutter
> > +          speed computed by the AE algorithm and it overrides any
> exposure mode
> > +          setting specified with controls::AeExposureMode. Similarly,
> when a
> > +          manual exposure time is set through controls::ExposureTime,
> it also
> > +          gets clipped to the limits set by this control. When reported
> in
> > +          metadata, the control expresses the minimum and maximum frame
> > +          durations used after being clipped to the sensor provided
> frame
> > +          duration limits.
> > +
> > +          \sa AeExposureMode
> > +          \sa ExposureTime
> > +
> > +          \todo Define how to calculate the capture frame rate by
> > +          defining controls to report additional delays introduced by
> > +          the capture pipeline or post-processing stages (ie JPEG
> > +          conversion, frame scaling).
> > +
> > +          \todo Provide an explicit definition of default control
> values, for
> > +          this and all other controls.
> > +      size: [2]
> > +
> >    #
> ----------------------------------------------------------------------------
> >    # Draft controls section
> >
>
> --
> Regards,
>
> Laurent Pinchart
>
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